module RailsConnector

  # This class provides an implementation for accessing the Verity based search server.
  # It should be customized by subclassing.
  class VeritySearchRequest
    attr_reader :query_string

    # Sanitizes the given +query_string+ and takes +options+ for accessing the SES.
    #
    # +query_string+ is a VQL search query.
    # +options+ is a hash and may be used to tweek the query.
    #
    # Options:
    # <tt>:host</tt>:: The SES server host, default: <tt>'localhost'</tt>
    # <tt>:port</tt>:: The SES server port, default: <tt>3011</tt>
    # <tt>:offset</tt>:: The search offset, default: <tt>0</tt>
    # <tt>:limit</tt>:: The maximum number of hits in the SearchResult, default: <tt>10</tt>
    # <tt>:min_relevance</tt>:: The minimum relevance in percent, default: <tt>50</tt>
    # <tt>:max_docs</tt>:: The maximum number of documents to be searched, default: <tt>'unlimited'</tt>
    # <tt>:parser</tt>:: The VQL query parser to be used, default: <tt>'simple'</tt>
    # <tt>:sort_order</tt>:: The sort order of the hits, a list of key-value pairs, each consisting of the sortkey and the sort direction ("asc"=ascending, "desc"=descending), default: <tt>[["score", "desc"], ["name", "asc"]]</tt>
    # <tt>:collections</tt>:: The collections to be searched, default: <tt>['cm-contents']</tt>
    # <tt>:base_query</tt>:: The VQL base query, default: <tt>nil</tt>
    def initialize(query_string, options=nil)
      @query_string = self.class.sanitize(query_string)
      @options = Configuration.search_options.merge(options || {})
    end

    # Accesses the SES and fetches search hits.
    #
    # Uses the #base_query and +options+ given in #new.
    def fetch_hits
      SES::VerityAccessor.new(vql_query_for(@query_string), {:base_query => base_query}.merge(@options)).search
    end

    # Removes unwanted characters from +text+.
    def self.sanitize(text) #:nodoc:
      text.strip.gsub(/[<>"'´`,()\[\]{}=!@\\]/, '')
    end

    def vql_query_for(query_string = '')
      words = query_string.split(/\s+/).map do |word|
        word unless %w(and or not).include?(word.downcase)
      end.compact.join(", ")
      "<#AND> (#{words})"
    end

    # Combines base query conditions to a single base query (see #base_query_conditions).
    #
    # A base query is used to reduce the number of documents before executing the actual query.
    # By default, all base query conditions must be met, they are combined using the +AND+ operator.
    def base_query
      "<#AND> (#{base_query_conditions.values.compact.join(', ')})"
    end

    # A hash of conditions, combined to a base query by #base_query.
    # Note that all values of the hash must be valid VQL syntax.
    # The keys have no meaning and exist only so single conditions can be replaced
    # in a subclass:
    #
    #   class SearchRequest < VeritySearchRequest
    #     def base_query_conditions
    #       super.merge(:content => '("edited" <#IN> state)'
    #     end
    #   end
    def base_query_conditions
      conditions = {}
      conditions[:objTypes] = '<#ANY> (
        ("generic" <#IN> objType),
        ("document" <#IN> objType),
        ("publication" <#IN> objType)
      )'
      conditions[:content] = '("released" <#IN> state)'
      conditions[:suppressExport] = '("0" <#IN> suppressExport)'
      conditions[:validFrom] = "(validFrom < #{Time.now.to_iso})"
      conditions[:validUntil] =  %!<#OR> (
                      (validUntil = ""),
                      (validUntil > #{Time.now.to_iso})
                    )!
      conditions
    end
  end

end